Question

Which elements would you expect to gain electrons in chemical changes? (a) nitrogen (b) iodine (c) tungsten (d) strontium (e) gold

Short answer

Nitrogen (a) and iodine (b) are expected to gain electrons in chemical changes.

Step-by-step solution

- Understand Electron Gain

In chemical changes, nonmetals tend to gain electrons to achieve a full valence shell, leading to a more stable configuration, which is usually the nearest noble gas configuration.

- Identify Nonmetals

Looking at the periodic table, identify which of the listed elements are nonmetals. Since nonmetals generally have higher electronegativities, they are more inclined to gain electrons during chemical changes.

- Evaluate Each Element

Examine each element individually: (a) Nitrogen is a nonmetal; thus, it will tend to gain electrons. (b) Iodine is a halogen, a group known for gaining electrons. (c) Tungsten is a metal and typically lose electrons. (d) Strontium is an alkaline earth metal, which usually loses electrons. (e) Gold is a transition metal and typically does not gain electrons. Therefore, the elements expected to gain electrons are nitrogen and iodine.

Key concepts

Valence Shell

In the world of atoms and their interactions, an important concept is the valence shell, which is the outermost electron shell of an atom in its uncombined state. These outer electrons determine the chemical behavior of the atom, including how it bonds with other atoms. Atoms tend to react in ways that can fill or empty their valence shells to reach a more stable state, often resembling the electron configuration of the closest noble gas.

For instance, nonmetals tend to gain electrons to fill their valence shell to achieve stability, akin to securing all the seats in a game of musical chairs when the music stops. This drive towards achieving a complete valence shell largely explains their higher likelihood of gaining electrons in chemical reactions.

Noble Gas Configuration

A noble gas configuration represents the ultimate goal for many elements undergoing chemical changes. Noble gases boast a full valence shell, making them particularly stable and generally inert. Atoms of other elements attempt to mimic this stability by adjusting their electron count—either by shedding electrons (if they are metals) or by acquiring extra electrons (if they are nonmetals), ultimately seeking the serenity of a full house just like the noble gases.

This desire for electron stability frames our understanding of why certain elements behave the way they do in reactions, offering a window into the underlying motives of their chemical character.

Periodic Table

The periodic table is like a grand atlas of elements, cataloging all known atomic types in an organized fashion based on their atomic number and electron configuration. It is divided into blocks, with each telling a story about the properties of the elements within. The table helps predict how an element might behave in a reaction, especially when it comes to gaining or losing electrons.

Metals, generally found on the left side of the periodic table, are prone to losing electrons. Conversely, nonmetals, which reside on the right side, exhibit a tendency to gain electrons. This layout is not arbitrary; it reflects the periodic trends in properties such as electronegativity, which guides us in predicting an element's chemical behavior.

Nonmetals

Nonmetals are the elements that are typically located on the right side of the periodic table. They boast a variety of physical states at room temperature—some are gases like nitrogen and oxygen, others are solids such as carbon and sulfur, while one, bromine, is a liquid. The common thread linking nonmetals is their propensity to gain electrons during chemical changes thanks to their higher electronegativities and not fully filled valence shells.

This electron hunger marks their role in forming molecules by sharing or accepting electrons. Through this behavior, nonmetals often partner up with metals or other nonmetals to achieve a more stable electron configuration. Examples include the oxygen we breathe and the chlorine used in pools, both eager electron grabbers in their own realms.

Halogens

The halogens form an electrifying group within the nonmetals, occupying Group 17 of the periodic table. This family, including fluorine, chlorine, bromine, iodine, and astatine, has a fierce reputation for their reactivity and strong desire to gain electrons. Their valence shells are just one electron shy of the noble gas configuration, which renders them among the most reactive elements.

During chemical changes, halogens are known to aggressively pull electrons toward themselves, creating ionic bonds with metals—like the sodium in table salt—or covalent bonds by sharing electrons with other nonmetals. The reactivity of halogens is such a standout feature that it significantly influences their uses in everyday life, from disinfectants to pharmaceuticals.

Electronegativity

Electronegativity is the measure of an atom's ability to attract and hold on to electrons when it is part of a compound. Think of it as a pulling power in the tug-of-war over electrons. Elements with high electronegativity, like those pesky halogens and their nonmetal cousins, are often the winners in this game, readily capturing electrons from less electronegative atoms during chemical reactions.

Understanding electronegativity gives us a forecast of an element's behavior: highly electronegative elements want electrons more and are thus more likely to gain them. This trend is beautifully portrayed in the periodic table, which shows electronegativity increasing from left to right and bottom to top. This property is not just an abstract concept; it has concrete implications in the formation of molecules and the unique character of chemical bonds shared between atoms.